Designing of super-elastic freestanding ferroelectric thin films guided by phase-field simulations

Understanding the dynamic behavior of the domain structure is critical to the design and application of super-elastic freestanding ferroelectric thin films. The phase-field simulation is currently a powerful tool for observing, exploring, and revealing domain switching behavior and phase transition in ferroelectric materials at the mesoscopic scale. The present review summarizes the recent progress of phase-field methods in the theoretical interpretation, mechanical response, and domain structure evolution of freestanding ferroelectric thin films, wrinkled structures, and nano-springs. Furthermore, the strong coupling relationship between strain and ferroelectric polarization in super-elastic ferroelectric nanostructures is confirmed and discussed, which brings new design strategies for strain engineering of freestanding ferroelectric thin film systems. To further promote the innovative development and application of the freestanding ferroelectric thin film system, the review ends with a summary and an outlook on the theoretical model of the freestanding ferroelectric thin film.